DEAR DR. ROACH: I’m planning on getting platelet-rich plasma (PRP) for my knee (due to arthritis and years of previous steroid/gel injections) as well as my large toe joint (due to a bone spur removal three years ago).

The most recent bone spur removal left very rough bone, causing periodic pain plus hyperesthesia in my toe. I am a 76-year-old male who is still active and not taking any regular medications. I do take ibuprofen prior to working out (pickleball, gym, biking and swimming).

What are your thoughts on this injection regimen, and why hasn’t the Food and Drug Administration approved it? Medicare won’t cover it. — C.H.

ANSWER: A 2023 review of 40 published trials found PRP injections for knee arthritis to be no more helpful than other injections, including steroids, hyaluronic acid or saline (depending on the study). The FDA didn’t approve it because of a lack of convincing evidence that it is more effective than other treatments, and Medicare won’t pay for it because the FDA didn’t approve it.

I certainly have had some patients note a dramatic improvement after PRP injections, but I have had other patients have a dramatic improvement with steroid injections. An expectation that you are going to get better and, honestly, the high out-of-pocket cost tend to make people feel like this is a very useful procedure.

While this might be proven ultimately, the evidence right now does not support the treatment, specifically for knee arthritis. I have some colleagues who believe that PRP is helpful with some kinds of acute trauma (such as tendon damage), but the evidence isn’t strong enough yet for me to have an opinion.

I don’t have the expertise to recommend a cheilectomy (the removal of a bone spur from a joint), but my most trusted consultants don’t recommend this treatment lightly.

DEAR DR. ROACH: What is Sjogren’s syndrome, and what does it do? Can you have Sjogren’s syndrome if you are seronegative with your only symptoms being dry eyes, dry mouth, some arthritis, and mild morning stiffness? What is the treatment if you’re diagnosed as seronegative? I am 73, and my only medication is pilocarpine for dry mouth. — F.S.

ANSWER: Sjogren’s disease is an autoimmune condition where the body attacks the glands of the eye and mouth, causing dryness. It is not common, with about one per 1,000 people affected. Many people report a gritty or sandy feeling in the eye. The lack of saliva can cause difficulty swallowing and changes in taste. Some people have difficulty speaking for long periods of time.

Dry mouth then predisposes people to advanced tooth decay, which is common. There are other organs that can be affected by Sjogren’s disease, including the skin, joints, lung, thyroid and nervous system. Sjogren’s disease can occur by itself or in association with other rheumatologic diseases.

The blood tests (serology) for Sjogren’s are imperfect. About 60% to 80% of people with SD will have antibodies, so there are a lot of people with seronegative disease. About 1% of healthy people who don’t have symptoms will have the antibody.

Dry mouth and dry eyes are very common in older adults (15% or more). The diagnosis of Sjogren’s over age 65 is unusual, so nearly all older people with your symptoms have age-related dry eye and mouth (as well as osteoarthritis in your case). There are saliva and eye tests that can be performed by experts, such as a biopsy of a salivary gland if the diagnosis is strongly considered in a person with negative blood tests.

In your case, pilocarpine, which is effective at increasing saliva production in people with SD, along with artificial tears may be the only treatments needed, whether you have Sjogren’s or not.